Navigating apparatus and method



March 5, 1929. E. L. HOLMES NAVIGATING APPARATUS AND METHOD 4 Sheets-Sheet Filed Jan. 23, 1925 INVENTOR BY @714 v/wee ATTORNEYS E. L. HQLMES 1,704,250

NAVIGATING APPARATUS AND METHOD March 5, 1929.

4 sneaks-sheet 2 Filed Jan. 23, 1925 r I -..1.........,1 19 i/flmmy-mmw-mm m i lllllmlmll k 5 INVENTOR BY @mt o /nae M ATTORNEY:

March 5, 1929.

E. L. HOLMES NAVIGATING APPARATUS AND METHOD Filed Jan. 23, 1925 4 Sheets-Sheet 5 ATTORNEYS March 5, 1929. ME 1,704,250

NAVIGATING APPARATUS AND METHOD Filed Jan. 25, 1925 4 Sheets-Sheet 4 UM r - mmmmm ulmnmmmnunw L-Ill INVENTOR Pmfm 1 ATTORNEYS Patented Mar. 5, 1929.

UNITED STATES 1,1o4,zso

PATENT oI-f'l-"lcs.

EDWARD L. HOLES, OI YORK, I. Y., ABSIGNOB TO HOLDS panama LI- PABLTUS 00., 110., O! m YORK, I. Y., .L CORPORATION 01 m YORK.

RAVIGAZ EING APPARATUS AND IEIEOD.

Application fled In!!! 18, 1825. Seth-1 Ho. 4,151.

The "following is a description of navigating apparatus and methods of operating the same embodying my invention in the form and manner. at present preferred by me; but it will be understood 'that various modifications and changes may be made without departing from the spirit of my invention and without exceeding the scope of my claims.

My invention will best be understood by reference to the accompanying drawings, in which I have illustrated the preferred form of devices for carrying out my invention, and in which Fig. 1 shows schematically the several units comprising the apparatus and a wiring diagram of an electrical system which may be employed in connection therewith; Fig. 2 is a perspective view showing a mastercompass and associated mechanical and electrical devices; Fig. 3 shoyvs in vertical section the various elements of a magnetic-compass and some of the elements of the master-compass and supporting means for said compasses; Fig. 4 is a top plan view of the magnetic-compass and of some of the mastercompass elements and the supporting means;

Fig. 5 is a front perspective view of a device which indicates path anddistance; and Fig. 6.is an end perspective view of the device of Fig. 5. Fig. 7 is a front elevation of a counter having attached to one dial thereof a. shutter for concealing the numbers of said counter, such shutter being shown as apartially broken away; and Fig; 8 is a section view of the counter illustrated in Fig. 7, showing the left-hand dial of said Fig. 3 partly in elevation and partly in section, to illustrate the manner of attaching said shutter to said dial. Like reference characters indicate like parts throughout the drawings.

My invention is particularly applicable to navigation. In the navigation of a ship or other mobile object there is a continual tendency toward angular deviation from the set path along which it is desired that the ship or other mobile object shall travel. For example, in the case of a ship, a number of causes, such as winds, cross seas and carelessness on the part of the helmsman, constantly tend to produce such angular deviations-these movements being known in navigation as yawing of the ship, and frequently.

amounting to several degrees. The helmsman on observing that the vessel is angularly dc parting from its set path can straighten the vessel to its" compass course, but there is no record left of its having departed from the set path, or of the angle of departure, or of the time during which it has traveled on the ofi course. Upon realizing that there has been angular deviation of the vessel from the set path, a skilful helmsman' endeavors to return to that path. However, this proceedmg is altogether a matter of guess work, be cause the set path is obviously merely an imaginary line in space. The net result is that the vessel, due to the foregoing causes, may, and in practice does, ireguently depart from the set path a distance 0 several miles between astronomical observations-obvious ly with consequent danger and uneconomical operation.

My invention provides an apparatus for readily determining at any time the then distance from the ship to the set path.

The apparatus afl'ords a path-and-position indicator, and comprises a magnetic-com as which, governs a magnetic compass w ich governs the master mechanism controlling what I term a ath-and distance indicator. This path-andistance indicator comprises a; repeater-compass which is responsive, through the master-compass, to the magneticcompass-together withintegrating and registering mechanism under the control of said repeater-compass. One side of the re compass pre counters, and the other side controls distanceindicator counters. The counters controlled bg the path-indicator side show whether the s i is on its set path or to the right or left of sai ath; and register a figure which, when multiplied by the speed of the ship, will at any time show the then distance of the shi from its set path. The counters controll by the distance-indicator side show the position of the ship with reference to its known point of departure, and re shot a figure which, when multiplied by t e speed 0 the ship, will at any time show the then distance between said point of departure and a projection of the ship upon the set ath. The chart position of the ship may lie readily found by correlating these. two figures. While the apparatus will be described as o crating one repeater-compass only, it will understood by those skilled in the art that it erably controls path-in icator,

may be employed to control any number of vices such as automatic steeringlmechanism,

course-recorders and path-andstance indicators.

Referring to the drawings (Fig.3), 1 indicates a liquid magnetic-compass comprising magnetic needles 2 and 2 mounted upon arms 3, carried by conical hub 4 (preferably of glass) containing jewel 5, forming a hearing for ivot 6, supported on post 7 integral with f ow-up compass bowl 8, formed o sulating material, such as glass. Arms 3 also carry annulus 9, (preferably of mica), upon jecting into said bowl are bowl conductors 14,

14, 14 and 14. Follow-up bowl 8 carries a cover 15 (preferably of glass), between which and said bowl is expansion chamber 16.

Mounted on cover 15 is master-compass card 17. Follow-up bowl 8 is supported on base 18 (Fig. 3), carrying follow-up bowl gear 19 and distributor rings 20, 20 and 20 electrically insulated fromsaidbase and electrically connected to followup bowl conductors 14, 14, 14 and 14. Attached to base 18 is shaft 21, operatively rotating in socket 22 on upper platform 23 of frame 24, suspended by bearings 25 and 25, tiltably supported on gimbal-ring 26, supported by bearings 27 and 27 (Fig. 4) on binnaclering 28, mounted on binnacle-stand 29. Also mounted on frame 24 is lubbers line bracket L, which h'asa lubbers line for the magneticcompass cardand also a'lubbers line for the mastencompass card. Mounted on upper platform 23 and electrically insulated therefrom are three brushes 30, 30 and 30", which operatively contact electrically with distributor rings 20, 20 and 20 respectively. Attached to the under side of upper platform 23 is follow-up motor 32, (Fig. 2) the arma ture shaft of which carries a worm (not shown) which drives a worm gear (not shown), mounted on shaft 33, which latter shaft also carries bevel pinion 34, meshing with and driving bevel gear 35, mounted on vertical shaft 36. Vertical shaft 36 carries at its upper end pinion 43, meshing with and driving compass bowl gear 19wherebyfollow-up motor 32 rotates said compass bowl.

Follow-up motor 32 has differential field windings 44 and (Fig. l) and receives cur rent from generator 46 or other suitable source of electrical energy. The lower end of shaft 36 carries spur gear 37, meshing with. and driving intermediate gear 38, integral with gear 39, mounted on a shaft having its bearing in lower platform 31 of frame which gear 39 in turn meshes with and drives transmitter shaft gear 40whereby followup motor 32 also rotates transmitter multiple brush 41, in electrical contact with transmitter distributor block 42.

The supply of current'from source 46 to follow-up motor 32 is controlled by the move- 'ments of armature 47 of relay 48, which armature carries springs 49 and 49. Attached to said armature are adjustable suspended control weights 50 and 50, the purpose of which will be hereinafter explained. The relay has adjustable contact members 51 and 51*, coacting with the contact members on the relay armature. The opposing adjustable electromagnet' coils 52 and 52 of said relay are continually energized by alternating current fiowin through the two circuits associated with t e follow-u bowl, included in which circuits is electroyte 12. Relay armature 47 responds to a differential in the current flowing through the follow-up bowl circuits and through the relay coils, in a manner to be hereinafter described.

Current from source 53 is conveyed through rotary transmitter 41-42 to, the field coils of reversible step-by-step motor 54, causing said motor to rotate intermittently and in either direction, in a well-known manner. Referring to Fig. 6, the armature shaft of step-by-step motor 54 carries spur gear 55, meshing with and driving spur gear 56, mounted on countershaft 57, carrying pi11- ion 58, meshing with and driving spur gear 59, mounted on countershaft 60, carrying pinion 61, meshing with and driving spur gear 62, mounted on repeatencompass shaft 63. Attached to the path-indicator, or left-hand, end of this latter shaft is a spoked wheel 64; and attached to the distance-indicator, or right-hand, end of said shaft is a spoked wheel 64. Mounted on the annular portion of spoked wheel 64 is path-indicator repeatercompass card 65; and on the annular portion of spoked wheel 64, distance-indicator repeater-compass card 65. Rotatably mounted on the left-hand end of repeater-compass shaft 63 is yoke 66, carrying at the outer end of one arm the set-screw 67 for clamping said yoke to the annular portion of spoked wheel 64. The opposite end of shaft 63 carries a corresponding and similarly mounted yoke 66 and set-screws 67 a for clam ing this latter yoke to the annular portion of spoked wheel 64. The other arm of yoke 66 carries at its outer end yoke-pin 68, engaging a vertical slot in cruciform yoke 69, supported by grooved rollers 70, 70 7 0 and 70 on yoketrack 71. Mounted on the lower portion of cruciform yoke 69 is an integrating unit, driven by integrating disk 76, and comprising integrating wheel 72, counter-driving shaft 73 (rotating in suitable bearings), and

. between the indicator, controlled by t counters 74 and 75, carried by said shaft, which counters constitute a path-indicator. Integrating wheel 72 is maintained in driving contact with path indicator integratin disk 76 by bar 7 7 pressed by sprin 78 an 79 against roller 80, mounted on t e lower end of cruciform yoke 69. Yoke 67 'has a yoke-pin engaging a corres ending cruciform yoke 69, supported in ike manner on a yoke-track 71, carrying a similar integrating unit comprising integrating wheel 72', a counter-driving shaft, and counters comprising a distance-indicator. A corresponding integrating disk 76 drives integrating wheel 72. Integrating disks 7 6; and 7 6 are driven, through speed-reduction gearing (not shown), by motor 81, which receives current.

from a suitable source of electrical energy, illustrated as a battery at 53 (Fig. 1). This motor 81, which rotates at a substantially uniform speed, also drives clock 82. The speed of motor 81 is regulated by a cam (not s own) operated by hand-wheel 83 (Fig. 6) and acting upon friction-brake governor 84, in a well-known manner. By comparison of this clock with a standard timepiece, the correctness or incorrectness of the motor speed may at any time be determined.

Repeater-compass card on the distanceindicator side is a duplicate of repeater-compass card 65, on the path-indicator side, except for the reversal of the figures thereon. Yoke 66, set-screw 67, the yoke-pin, cruciform yoke 69*, the cruciform yoke rollers,

yoke-track 71, together with the integrat mg unit and its associated parts, on the distance-indicator side of the apparatus are in all respects duplicates of the corresponding arts on the path-indicator side thereof.

owever, for reasons which will be hereinafter set forth, the operative relationship distance-indicator cruciform yoke and its yoke-pin is not the same as the operative relationship between the corresponding path-indicator elements, but is at an angle of 90, thereto.

The repeater-compass, together with its as-- sociateddevices, may be installed in the pilot house, where it may serve as a steering compass. The purposes of the path-and-distance e repeater compass, are: (1) to indicate at a glance when the ship is on its set path, or the direction to the right or left resulting from any angular travel of the ship with reference to said set path; (2) to provide simple means for quicky determining at any time the distance, if

" any, which the ship may then be from its set path; and, (3) to provide means for readily determining at any time the distance between a known point of de arture and the projection of the ship upon t e set path. By combining the indication as to the distance, if any, of the ship from its set path, and the indication of the distance between its known point ofdeparture and its projection upon said set ath, the osition of the ship, in terms of titude an longitude, may quickly be determined.

The modecf operation of the apparatus is as follows: binnacle-stand 29 is attached in the usual manner to a mobile ob'ect, such as a ship. Initially, follow-up bow 8 and mag netic compass needles 2 and 2 may not be 1n proper operative relationship, and in order to bring these elements into such relationship, switch 841 (F' 1) is manually closed, and rela armature 4 is manipulated to close one or ot er of the circuits which include follow-up motor 32. The rotation of said motor in the. proper direction turns follow-up bowl 8, and thus brings bowl conductors 14 and 14" approximately opposite the downwardly-projecting portions of compass card conductor 11; and bowl conductors 14" and 14 approximately opposite the downwardly-projecting portions of compass card conductor 11. This operation also brings master-compass card 17 into approximate alignment with magnetic-compass card 10. Switch 85 is then manually closed, and the master-compass will thereafter automatically control the devices which may be electrically connected to it.

With the compass bowl conductors and the compass card conductors in alignment, substantially the same amount of current flows through the circuit which includes lines 86 and 87, coil 52, lines 88 and 89, compass bowl conductor 14, electrolyte 12, compass card conductor 11, electrolyte 12, compass bowl conductor 14',' 1i'ne 90, switch 85 and line 91 as flows through the circuit which includes lines 86 and 92, coil 52', lines 93 and 94, com pass bowl conductor 14, electrolyte 12, compass card conductor 11, electrolyte 12, compass bowl conductor 14", line 90, switch 85 and line 91. The energization of rela coils 52 and 52' is therefore practically equa and re lay armature 47 remains in a' neutral position in which it closes no secondary circuit.

After follow-up bowl 8 has been brought purpose of illustration, will be assumed to be 50 east of north), the repeater-compass shown in Fig. 5 is brought into synchronism with the master-compass in the following manner: with transmitter switch 95 open, no current flows through step-by-step motor 54 and repeater-compass shaft 63, together with its attached compass cards, is freely rotatable. Repeater-compass shaft 63 is now manually rotated until points 50 on the two repeatercompass cards register with repeater-compass lubbers lines 96 and. 96. When the ship is exactly on its set path, as indicated by figure 50 on master-compass card registering with master-compass lubbers line, transmitter switch 95 is closed. This results in the energization of some of the field magnets of step-by-step motor 54, whereby the repeatercompass becomes electromagnetically locked to the master-compass, and hence will subsequently follow all variations of the mag netic-compass, because the magnetic-compass controls the master-compass which operates relay 48, the relay controls follow-up motor 32, driving transmitter 4142, which in turn controls the direction and extent of rotation of step-by-step motor 54, driving repeatercompass shaft 63. It will be apparent that the device is universally adjustable to operate in reference to any desired path to which the repeater-compass shaft 63 and the integrating device may be initially set.

In order to bring the path-and-distance indicator under control of the repeater-oompass, set-screws 67 and 67 on the path-indicator and on the distance-indicator sides of the device are released, and cruciform yokes 69 and 69 are moved until the yoke-pointers register with the figure on the compass cards which represents the set path-which figure is in this case assumed to be 50. When in this position of registration, set-screws 67 and 67 are clamped to spoked wheels 64 and 64, respectively, which carry repeater-compass cards 65 and 65"-thus coupling yoke 66, to-

. gether with its cruciform yoke 69, and yoke 66, together with its cruciform yoke 69*, to

repeater-compass shaft 63, so that any subsequent rotary movement of said repeatercompass shaft, in response tothe action of the master-compass, will produce a corresponding change in the position of cruciform yoke 69 on its yoke-track 71, and in the position of cruciform yoke 69 on its yoke-track 71, thereby shifting integrating wheels 72 and 7 2 in one direction or the other along the faces of integrating disks 76 and 76. After the 1 repeater-compass has been synchronized with 1 the master-compass, and the cruciform yokes ad usted to the set path, all four counters are brought to zero. Switch 105 is then closed, and thereafter motor '81 will, through suit-.

able speed-reduction gearing, drive integrating disks 76 and 7 6 and thus rotate counterdriving shafts 7 3 and 7 3 at speeds correlated I to their respective positions of contact with the faces of said integrating disks. So long as the ship remains on its set path, as, for

example, the assumed path of 50 east of north, the yoke-pin pointers and the figures 50 of the two repeater-compass cards 65 and 65 will register with repeater-com%s lubbers lines 96 and 96", respectively. en in this position, integrating wheel 72 on the path-indicator side of the device remains at the center of continuously rotating integrating disk 76, and therefore is not driven there by. Yoke 66 on the distance-indicator side of the device is set in such a manner that its yoke-pin, engaging the coacting cruciform yoke, is operatively in a position 90 from the position of the corresponding yoke-pin on the path-indicator side-this offset being in a clockwise direction from the viewpoint of facing the respective compasscards. Distance-indicator integrating wheel 7 2 is at its maximum outward position with reference to its driving disk when path-indicator integrating wheel 72 is at the center of its driving disk.

Assuming now that the ship veers 1 to the right: compass needles 2 and 2", together with magnetic-compass card 10, will remain stationary in space, while the remainder of the compass structure, including. follow-up bowl 8, will be displaced with reference to said compass needles, the movement of the bowl being in a clockwise direction. As soon as this displacement reaches one-sixth of one degree, the device operates for the reasons and in the manner following: because of the form of bowl conductors l4, 14, 14;" andll, and of compass card conductors 11 and 11", respectively, and because of their relative positions, this displacement by one-sixth of one degree of the follow-up bowl 8 does not materially change the length of the electrolytic paths between bowl conductors 14 and 14 and the coacting downwardly-projecting ends of compass card conductor 11. Therefore the resistance of the circuit which includes rela coil 52 remains substantially unchanged. owever, this clockwise movement of follow-up bowl 8 does increase the length of the electrolytic paths between compass -bowl conductors 14 and 14 and the coacting downwardly-projecting ends of compass card conductor 11, resulting in an increase in the resistance of the circuit which includes relay coil 52*; and this increase in resistance reduces the energization of relay coil 52, permitting relay coil 52 to attract relay armature 47 and bring the same into contact with contact member 51. This closes the following circuit: from one terminal of source 46, line 97, switch 841, lines 98 and 99, relay armature 4,7, relay contact member 51, lines 100,101, 106 and'107, motor field winding 45, armature of motor 32, lines 102, 103, 104 and 91, to opposite terminal of source 46. Thereupon follow-up motor 32 rotates in a direction to return follow-up bowl 8 to a position wherein the resistances of the two electrolytic circuits which include relay coils 52 and 52 reach such values as to practically equalize the energization of such coils and thus'bring relay armature 47 into its neutral position-thereby opening the circuit which includes the follow-u motor and stopping said motor. While f0 ow-up motor 32 was rotatin f0 low-up bowl 8 m a counter-clockwise tion to re-establish the initial relationship between compass needles 2 and 2 and the follow-up bowl and its elements, said motor was also rotating transmitter 41-42, driving step-b -step motor 54, turning repeater-compass s aft 63,- and thereby rotating the pathindicator com ass in a counter-clockwise direction and t e distance-indicator compass in a clockwise direction, one-sixth of one degree with reference to their respective lubbers lines 96 and 96. With each successive deviation of the ship by one-sixth of one degree, there is a recurrence of this cycle of operation, until the total deviation of the assumed 1 has occurred.

The 1 counter-clockwise rotation (as viewed from the path-indicator side) of repeater-compass shaft 63 has, through yoke 66 and yokein 68, moved cruciform yoke 69 (Fig. 5) slightly to the left upon its yoketrack 71, thereby shifting path-indicator integrating wheel 72, relative to the face of integrating disk 76, from its central, or nondriven, position. The position, and consequently the speed, of integrating wheels 72 and 72 is controlled, through the magneticcompass, the master-compass and the repeater-compass, by the travel of the ship with reference to its set path; and the angle of deflection of the repeater-compass always coincides with the then angle of travel of the ship, with reference to said set path. The

lined speed of the integrating disks is such that any angular travel of the ship with reference to its set path moves the path-indicator integrating wheel to such a position as to cause the integrating disk to rotate said wheel at a speed resulting in the registration by one of the path-indicator counters of a figure representing the sine of the angle of travel, multiplied by the time in hours which its counterdriving shaft. has rotated. This figure will continue to increase so long as the ship is traveling away from its set path. Thus, at the end of one hour of operation, under the 1 condition of travel at the assumed 1 from the set path, the path-indicator counter nearest said set path will register 0.0174, which is the sine of the angle oi: 1. If the ship has meanwhile traveled one nautical mile, its distance from its set path, at the end of such hour, will be .0174 of a nautical mile. If it has traveled 15 miles (as determined by any of the methods well known in navigation), it is only necessary to multiply such registered figure 0.0174 by 15 to learn the distance (.261 of a nautical mile) which the ship is at that time away from its set path. The path-indicator counter registration being, as stated, the sine of the angle of travel of the ship, multiplied by the time, in hours, which its counter driving am has 0 ma istration will, when multiplilsd ekndsr n' speed of the shi give at anytime the then istance of the s hip from its set path. The direction in which the ship has veered is indicated by the fact that the figures of the counter nearest the set path are exposed, while those of the opposite counter are con- If the ship be brought'to a course parallel to its set path, there will be no subsequent change in this registered figure so long as this parallel course is maintained, because the'integrating wheel will have been returned to the center of the integrating disk, where it ceases to rotate. When, however, the ship is headed toward its set path, the apparatus will operate in a direction opposite to that in which it operated while the shi was departing from its said set ath, with t e result that the figure registers by the path-indicator counter will continuall decrease until the set path is reached, w en such figure will again become zero. .When the ship is on its set path, each of the pathdndicator counters registers zero. Thus the path-indicator integrates and registers the values, in terms of sines, of all angles of travel with a factor of all the various distances involved in such travel, with reference to any set path.

The distance-indicator side of the .device operating at from the course-indicator side, the figure registered by one of its counters represents the cosine of the angle of travel. multiplied by the time in hours which its counter-driving shaft has rotated. With the assumed travel at an angle of 1 from the set path, the distance-indicator integrating wheel will be moved slightly toward the center of distance-indicator integrating disk 76. The right-hand distanceindicator counter will, at the end of one hour of operation, register 0.9998, which is the cosine of the angle of 1. If the ship has meanwhile traveled one nautical mile, it will have made good a distance of .9998 of a nautical mile as measured in a direction parallel to the line of its set path. If it has traveled 15 miles in that hour, the distance made good will be 15 X .9998, or 14.997 nautical miles, Thus the distance-indicator integrates and registers the values, in terms of cosines, of

all angles of travel with a factor of all the.

various distances involved in such travel with reference to any point of departure and any set path. I

With the direction and distance of the ship from its set path known, and with the distance known which has been made good on or parallel to its set path from a point of departure of determined latitude and longitude, the actual position of the ship, in terms of latitude and longitude, is at any time easily ascertainable. Actual tests aboard ship have shown that the device is very accurate, registerixig chan es in direction of the ship as small as one-sixth of one degree.

The counters are of the reversible type, one of each pair being right-hand drive and the other left-hand drive. When the ship is initially brought to its set path, all counters are set at zero. If the ship veers to the right,-the figure showin on the left-hand filth-indicator counter Fig. 5) increases. gimultaneously, a shutter, such as 7 5' (Figs.

7 and 8), automatically covers the negative,

or decreasing, figure on the right-hand pathindicator counter. I believe the expedient of exposing one counter and covering the opposite counter is novel in this art; and it possesses the advantages of instantly indicating the direction in which the set path lies, and of obviating the confusion which might result from the necessity of considering the values of two sets of exposed figures. Further, in crossing the set path, one shutter will automatically close, while the opposite shutter will automatically open; and this alternate closing and openin constitutes a practical and readily-observab e guide which permits of more accurate steering than is possible with any other apparatus or by any other methods with which I am familiar. The shutters are caused to operate in the described manner by attaching them over the highest digit of the highest dial of each counter, in which position they respond immediately to the reversal of the counter-driving shaft which produces a negative reading,

I am aware that it has heretofore been proposed to utilize movements relative to the needle of a magnetic compass to actuate various external devices. For example, many attempts have been made to cause such movements to close metallic contacts in electric circuits. However, the force exerted by the earths magnetic field upon a compass needle is inadequate to ailord sufiicient pressure to close such contacts without seriously inter ferring with the action of the needle.

It has also been attempted to utilize asa portion of electric circuitscontrolled by move-' ments relative to the needle of the magnetic compass, an electrolyte in which the magnetic needle is immersed-direct current being conveyed through two circuits which include the electrolyte. I have found that such an arrangement is inoperative forthe reason that any compass change unbalances the resistances of the electrolytic portions of the cir cuits, greatly disturbing the constant-polarity magnetic field which is associated with every circuit carrying direct current, and thereby pi'oduoing'a de ection of the compass needle.

oreover, if indestructible conductors, such as carbon, be employed in an electrolyte, direct current decomposes the electrolyte, re sulting in the evolution of gases, which, in the form of bubbles, adhere'to the conductors, the compass bowl, and the compass card.

These bubbles produce changes in resistance in the electrolytic circuits, and also result in friction and capillary attraction between the moving arts. If direct current is employed, this evo ution and deposition of gases occurs with all combinations of electrolytes and conductors except when pure metallic conductors are used in combination with an electrolyte containing a salt of the metal comprising one of the conductors. Under these conditions, "5 gas bubbles do not collect, but a plating action occurs which results in the disintegration of the conductors which constitute the anodes, and in the building up of the conductors which constitute the cathodes.

It has also been attempted to cause a master-compass to follow a magnetic-compass by utilizing the diilerential in resistance between two electrolytic circuits carrying direct current to act upon magnetic brakes. Such systems are predicated upon the tallacious assumption that the resistance of an electrolvtic circuit, like that of a metallic circuit, is directly proportional to the length of the path. This is not the fact, and such a master-compass cannot faithfully reproduce movements relative to the compass needle.

, ln attempts to utilize movements relative to the magnetic-compass needle, it has been proposedto convey electric current to conductors through the pivotal bearing of the compass card. Such devices are impracticable lor the reason that the compass card bear-in must, under this condition, necessarily e metallic and of very minute area; 100 and therefore any slight jarring which tends to separate the bearing elements causes areing, with consequent fusion-thus quickly destroying the bearing. In my apparatus, the curreilt is conducted directly through the 105 electrolyte and conductors which are separate from the compass pivot, thereby obviating the defects above reierred to.

I overcome the objections inherent in systems wherein the compass needle or compass 110 card is caused to close metallic contacts in electric circuits by allowing my compass card to move freely in a fluid and without other physical external contact than the necessary pivotal bearing contact. The respon- 115 siveness of the directional element of my com- .pass to the earths magnetic field is therearouse that it produces no plating action, and that its decomposing eflect upon an electrolyte is much less than that of direct current. In,

fact, I have found that by employing an electrolyte composed of equal parts of distilled sult of decomposition of the electrolyte.

Such an electrolyte does not freeze at ordinary temperatures, which is an important practical consideration. Further, under these conditions a very small movement relative to the magnetic-com ass needles produces a marked differential etween the resistances of the electrolytic circuits.

Referring to Fig. 3; in order to protect the metallic portions of the compass card (which portions ordinarily consists of iron, copper and brass) from electrolysis, I so mount the compass card as to bring it above the level of the electrolyte, and immerse it in abody of liquid of high dielectric strength, such as mineral oil, floating upon said electrolyte and not miscible therewiththus efiectually insulating such metallic portions from current flowing through the electrolyte. By so mounting the compass card, the only metallie portions associated with the card which are in contact with the electrolyte are the platinum-iridium pivot upon which the card is supported and the downwardly-projecting ends of the two platinum conductors 11 and 11. Under the conditions I have above described, neither platinum nor platinumiridium is subject to electrolysis, when entirely immersed in the electrolyte. I have found, however, that at the juncture of the electrolyte and the insulating liquid, gas bubbles form upon the platinum conductors, which evidences decomposition at this oint of either the electrolyte or the insulating liquid, or perhaps of both. In order to prevent this action, I preferably insulate the platinum conductors by fusing vitreous material thereon for some distance above and below the point where they are to contact with the j unctuae of the electrolyte and the insulating liqui I utilize the differential between the resistances of the electrolytic circuits to actuate a sensitive relay which, in turn, controls a follow-up motor driving both 'thefollowup bowl and a transmitter which governs the repeatencompass. I am thus enabled to operate my apparatus with a current as low as 35 milliamperes flowing through each of the electrolytic circuitsthe relay responding to '& diflerential as small as 8 milliamperes. /With a movement of the ship, and, therefore, of the follow-up bowl, as slight as one-sixth of one (1 this relay closes the follow-up motor circuit; and the motor thereupon turns the follow-up bowl and the repeater-compass shaft one-sixth of one degree in the op ite direction-the rate of this movement i ly in excess of the rate of movement 0 t e ship. When the follow-up bowl has been returned to its original position, the follow-up motor stops-the equilibrium of theelectrolytic circuits having been restored. As the ship continues to deviate from its course, this step-by-step counter-rotation of the follow-up bowl and of the repeater-compass shaft recurs at each one-sixth of one degree-the relay each time opening the follow-up motor circuit upon a restoration of the equilibrium in the electrolytic circuits. Therefore, in my system, instead of attempting to utilize a progressively-increasinge ectrolytic resistance caused by a continuing deviation of the ship (which resistance, as I have explained, is not directly proportional to the chan es in the length of the electrol ic path), repeatedly utilize small, de nite and uniform resistance changes to produce step-by-step movements throughout the time in which the deviation occurs. Thus, the fact that the electrolytic resistance is not directl proportional to the changes in the length 0 the electrolytic path becomes of no consequence in the operation of my apparatus, because such operation is by current increments and decrements which are always correlated to the same diiierential in resistances.

In order to insure that the operative differential will effect a continuous contact between the relay armature contact members and their coacting contact members, I over come the vibratory efifect upon such contact of the alternating current passing through the relay coils by opposing gravitational force to the force of ma etic attraction of the armature. I accom 'sh this result by suspending weights attac ed to threads supported between both sides of the upper end of the armature and stationa ints. I have found that by this means, arid h; carrying the armature contact members on springs of suitable ten sion, a difierential of 3 milliamperes will produce a continuous contact-all vibration between the armature contact members and their coacting contact members being elim since and cosines of angles of movements with distances of such movements, and with reference to a set path and a known oint of departure, they are subject to the 0 jection that in order that the movements of the stylus used in connection therewith shall be of any advantage as a steering guide relative to a set path, the chart must be impracticably large. If large-scale charts be employed, they must be frequently changed. Moreover, the integration results on such charts are not shown in figures, and distances must therefore be measured and computed. My apparatus is operatively independent of charts and their size limitations. Its speed of operation is preferably such that the counter registrations are in terms of one ten-thousandths of a nautical mile-thus constituting it a very sensitive and legible indication for steering purposes of departures from set path. In order that a chart might beequally legible, it would require to be on a scale of about 175 lineal feet per hour. If such a chart were intended to be used in connection with maneuvering, it would require to be proportionatevantages over chart-recording devices of registering clearly-observable figures which re quire but a simple multiplication to convert them into the desired terms of distance from set path and from point of departure; and

. of operating upon a scale very much larger than is feasible with a chart-recorder.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In navigation, the combination of a directional element adapted to be carried by a mobile object, integrating apparatus governed by said directional element, and a\ steering-guide actuated by said integrating apparatus and adjustable to indicate the direction of any set path for registering in numbers a. factor of the distance of said mobile object from said path.

2. In navigation, the combination of anume her-indicating steering-guide adapted to be carried by a mobile object, means for actuating said steering-guide, and compass-controlled means also adapted to be carried by the mobile object and responsive to angular movements thereof relative to any set path for governing said actuating means to cause said steering-guide to indicate a factor of the distance from said set path to said mobile object.

3. In navigation, the combination of a number-indicating steering-guide adapted to be carried by a mobile object, a motor for actuating said steering-guide, and means ad FLYOQQW justable to indicate the direction of any set path and also adapted to be carried by said mobile object and responsive to angular movements thereof relative to said set path for governing the indications of said device.

4. In nav1gation,- a number-registering steering-guide adapted to be carried by a mobile object and to be adjusted to operate with reference to any set path, actuating means for said steering guide, a follow-up compass bowl containing an electrolyte and also adapted to be carried by the mobile object, and electric circuits including an electrolyte and varying in resistance throt 'h changes in the length of paths through said electrolyte produced by angular movements of said obj ect relative to the set path to which said steering-guide has been ad usted to govern said actuating means and cause said steering-guide to indicate in numbers a factor of the distance from said set path to said mobile object.

5. In navigation, the combination ofa number-registering steeringguide adapted to be carried by a mobile object and constructed and arranged to be adjusted to operate with reference to any set ath for indicating a lactor of the distance irom the set path to said mobile object, a motor for actuating said device, and a follow-up compass bowl also carried by said mobile object and rotatable with reference thereto in response to angular movements or said object relative to the set path for governing the indicatii'ms of said. steering-guide.

6. In navigation, the combination oil. a number-registering steering-guide adapted to be carried by a mobile object, means for adjusting said steering-guide to operatewith reference to anyset path, and means respon sive to angular deviations of said mobile object/from the set path for governing said steering-guide to indicate the results of integrations of functions of angles with a factor of distances of travel of said mobile object relative to the set path.

7. The method of navigation which con sists in heading a mobile object along any set path defined by a line of direction passing through a known point of departure, indicating said line of direction, integrating relative to said indicating line a factor of dlstance of travel with a function-of angles of travel of the mobile. object with reference to the set path, indicating by numbers the results of such integration in order continuously to show the location of the set path, and steering the mobile object in accordance with such indication.

EDWARD L. HOLMES. 

